LECTURE 5 and 6 question solid waste.pptx

Questions in solid waste management

1. MI 362 Solid Waste Infrastructure Design and Management For the Third year, BSs MISE and EE – Sem II- 2024 By Mapinduzi and Helandogo

2. 2 Solid Waste management cycle Identify waste type Waste source Determine potential hazard Determine volume Determine collection/storage methods & transportation method Determine disposal method Households, Aid Agencies, Communal areas (markets), Industries, Medical facilities Faecal contamination, Flies, rats, cockroaches, chemical contamination, Fire risk, etc. Household containers, Small collective containers, Waste collection depots Burning, Burying, Composting. Organic waste, paper, cans, bottles, plastic packaging, dead animals, oil, chemicals, medical, concrete, stones, etc. 1 person / 0,5-1 liter of refuse / day organic content of 25-35 %.

3. COLLECTION METHODS

4. COLLECTION METHODS Types of Collection services Curb ( Kerb -side ) Alley Set out Backyard/Set out and set back

5. COLLECTION METHODS Collection means/stages

6. COLLECTION METHODS

7. COLLECTION METHODS

8. COLLECTION METHODS Comparison of Residential collection services Requires home owners cooperation Require schedule service for home owner cooperation Spillage and litter problem Containers visible Attractive to scavengers Prone to upsets Average crew requirement Crew time Crew injury rate Cost of crew and time

9. COLLECTION METHODS Frequency of collection Dependence Frequency of collection based on waste types Importance Methods of Loading the Solid waste to Vehicles Dependence and Means or types of loading solid waste

10. COLLECTION METHODS Developing collection routes The problem of designing a route so as to eliminate all deadheading was actually addressed as early as 1736. The brilliant mathematician, Leonhard Euler, was asked to design a route for a parade across the seven bridges of Königsberg, a city in eastern Prussia, such that the parade would not cross the same bridge twice but would end at the starting point.

11. COLLECTION METHODS

12. COLLECTION METHODS Developing collection routes Micro routing and macro routing The most efficient collection route criteria Heuristic Route Development, understand a manual approach Rules for Heuristic Routing(11 rules read and understand them) Labor requirement for the collection of solid waste

13. COLLECTION METHODS Rules for Heuristic Routing(11 rules read and understand them) Routes should not be fragmented or overlapping. Each route should be compact, consisting of street segments clustered in the same geographical area. Total collection plus hauling times should be reasonably constant for each route in the community (equalized workloads). The collection route should be started as close to the garage or motor pool as possible, taking into account heavily traveled and one-way streets . Heavily traveled streets should not be collected during rush hours.

14. COLLECTION METHODS Rules for Heuristic Routing(11 rules read and understand them) In the case of one-way streets, it is best to start the route near the upper end of the street, working down it through the looping process. Services on dead-end streets can be considered as services on the street segment that they intersect, since they can only be collected by passing down that street segment. To keep left turns at a minimum, collect the dead-end streets when they are to the right of the truck. They must be collected by walking down, backing down, or making a U-turn.

15. COLLECTION METHODS Rules for Heuristic Routing(11 rules read and understand them) Waste on a steep hill should be collected, when practical, on both sides of the street while vehicle is moving downhill. This facilitates safety, ease, and speed of collection. It also lessens wear of vehicle and conserves gas and oil. Higher elevations should be at the start of the route. For collection from one side of the street at a time, it is generally best to route with many clockwise turns around blocks.

16. COLLECTION METHODS Rules for Heuristic Routing(11 rules read and understand them) Note: Heuristic rules 8 and 9 emphasize the development of a series of clockwise loops in order to minimize left turns, which generally are more difficult and time-consuming than right turns. Especially for right-hand-drive vehicles, right turns are safer. For collection from both sides of the street at the same time, it is generally best to route with long, straight paths across the grid before looping clockwise. For certain block configurations within the route, specific routing patterns should be applied.

17. COLLECTION METHODS

18. COLLECTION METHODS The overall collection vehicle routing consists of three parts: The division of the collection area into smaller districts, each of which generates one load of refuse Determination of the vehicle path or tour from its entry into the district until its departure The aggregation of the districts and their associated tours into a full day’s workload for the vehicle and crew, which is called a route

19. COLLECTION METHODS Definition of a Unicursal Network/Euler Tour The network must be connected so that there is a way from every node to every other node, and The number of links touching every node (called the degree of the node) must be even. A network that is connected and has all nodes of even degree (and therefore has an Euler tour) is called a unicursal network.

20. COLLECTION METHODS Building a Unicursal Network/Euler Tour

21. COLLECTION METHODS Building a Unicursal Network/Euler Tour

22. COLLECTION METHODS Building a Unicursal Network/Euler Tour

23. COLLECTION METHODS Types of Collection Systems Classification based on mode of operation Classification based on equipment used Classification based on type/phases of solid waste collection Four unit operations in MSW collection system Pick-up Haul At-site Off-route/site

24. COLLECTION METHODS Four unit operations in MSW collection system Pick-up In HCS (conventional and exchange mode) and SCS Haul At-site Off-route/site

25. COLLECTION METHODS Four unit operations in MSW collection system Pick-up In HCS (conventional and exchange mode) and SCS Haul At-site Off-route/site

26. COLLECTION METHODS HAULED CONTAINER SYSTEM The time required per trip, which also corresponds to the time required per container, is given by: Where Thcs = Time per trip for hauled container system, h/trip Phcs = pick up time per trip for hauled container system, h/trip s = at site time/trip h= Haul time/trip

27. COLLECTION METHODS HAULED CONTAINER SYSTEM From experience haul time may be approximated by: Where: a. = Empirical constant h/trip b. Empirical constant h/mi x. = Round trip head distance mi/trip Therefore:

28. COLLECTION METHODS HAULED CONTAINER SYSTEM And the pick-up time for haul container system (P HCS ) per trip for the haul container system is: P HCS = pc + uc + dbc pc = time required to pick up loaded container uc = time required to unload empty container dbc = time required to drive between container location Therefore: T HCS = pc + uc + dbc + s + a + bx

29. COLLECTION METHODS The number of trips that can be made per vehicle per day with a hauled container system can be determined by: H = Length of work day h/day W= Off-route factor, expressed as a fraction t1=time required to drive from dispatch station to the first container location. t2=time to drive from the last container location to the dispatch station. Thcs = Time per trip for hauled container system, h/trip

30. COLLECTION METHODS The number of trips required per day can be estimated by the following expression: Vd = daily waste generation volume per day c = Average container size, volume/trip f = Weighed average container utilization factor.

31. COLLECTION METHODS STATIONARY CONTAINER SYSTEM For system using self loading collection vehicles, the time per trip could be found out using the following equation. T SCS = P SCS + s + a + bx Pscs . = pick up time per trip for stationary container system, h/trip

32. COLLECTION METHODS STATIONARY CONTAINER SYSTEM For stationary container system, the pickup time is given by: P SCS = c t (uc) + (n p - 1)( dbc ) Where: Pscs = pickup time per trip of stationary container system C t = No. of containers emptied per trip Uc = Average unloading time per container n p = No. of containers per pick up location per trip dbc = average time spent driving between container locations, h/container

33. COLLECTION METHODS STATIONARY CONTAINER SYSTEM The number of containers that can be emptied per collection trip is related directly to the volume of the collection vehicle and the compaction ratio that can be achieved. Thus: Where Ct = No. of containers emptied per trip v = volume of collection vehicle volume/trip r = compaction ratio volume/container c = container volume f = weighed average container utilization factor

34. COLLECTION METHODS STATIONARY CONTAINER SYSTEM The number of trips required per day can be estimated by using: Where: Nd = No. of collection trip per day Vd = daily waste generation v = volume of collection vehicle volume/trip r = compaction ratio volume/container